A Novel Powerful Choline Chloride - Thiourea/Sulfuric Acid: An Efficient and Recyclable Catalyst Used for the Microwave-assisted Synthesis of Quinazolin- 4(3H)-one Derivatives Used as Antibacterial Agents in Green Media

Abstract

Background: Choline chloride-thiourea/sulfuric acid is a powerful and efficient green catalyst used for one-pot synthesis of quinazoline-4 (3H)-one derivatives via a reaction between various amines, acetic anhydride, and anthranilic acid under microwave irradiation and solventfree conditions (4a-q). Microwave irradiation, which is a faster, more cost-effective, less energyintensive, and more efficient method than conventional heating, has been used to synthesize some quinazolinone derivatives. Introduction: For the past ten years, one of the major subjects in synthetic organic chemistry has been green synthesis, which has used efficient and environmentally friendly methods to synthesize biological compounds. The use of catalysts has significant advantages, including ease of preparation and separation, chemical and thermal stability, and environmental friendliness due to features such as reusability, low cost, and efficient and easy workup techniques. Therefore, the mechanism is performed by a non-toxic organic catalyst that uses the least amount of energy and chemical reactants in accordance with the principles of green chemistry and the least waste. Methods: One-pot and sequential addition methods have been used to synthesize quinazolinone derivatives. In the sequential addition method, the reaction was started by adding acetic anhydride and anthranilic acid to the reaction vessel under microwave irradiation and continued by adding choline chloride thiourea/sulfuric acid as efficient, recyclable green catalysts and the desired amine. In vitro, the well diffusion method against different pathogenic strains was used to evaluate the antimicrobial activity of quinazoline-4 (3H)-one derivatives. Pathogenic strains used were Candida albicans ATCC 10231 (yeast), Aspergillus niger ATCC 16404 (fungus), Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 (bacteria) and ATCC 6538, and Staphylococcus aureus S. epidermidis ATCC 12228. Pyrimidine-containing compounds, in which the 3- hydroxyl, 2,5-dimethoxy, 4-bromo, 4‐methoxy, and 4‐chloro groups are attached to the phenyl ring of pyrimidine, exhibit antimicrobial properties. Results: In a short reaction time, a variety of biologically active quinazolinone derivatives were synthesized with high efficiency. According to the results, it was found that with aliphatic amines, the reaction time was shorter, and the reaction efficiency was higher. Products synthesized from aromatic amines had more antibacterial properties. Conclusion: In this work, a variety of 2-methyl-quinazoline-4 (3H)-one derivatives (4a–q) were synthesized as potent antibacterial agents under microwave irradiation and solvent-free conditions in the presence of ChCl-thiourea/H2SO4 as an efficient, eco-friendly, and recyclable catalyst.